Compressor muffler construction

ABSTRACT

A muffler construction for a hermetic compressor wherein the muffler is made up of half-shell body and cover members connected together with their open ends facing one another and having matching ribs arranged at an acute angle to the gas flow path between the inlet and outlet of the muffler. The surfaces of the juxtaposed peripheral walls and ribs adjacent the open end of each member are coplanar. A flat sealing gasket is disposed between the members coextensive with the juxtaposed surfaces of the peripheral walls of the members. Hence, the gasket serves to space the juxtaposed surfaces of the ribs a predetermined distance apart to thereby define wide and thin flow passages successively communicating the muffler chambers formed by the transverse ribs and associated side and end walls of the members.

United States Patent Hover [54] COMPRESSOR MUFFLER CONSTRUCTION [72] Inventor: Paul B. Hover, Clinton, Mich.

[73] Assignee: Tecumseh Products Company,

Tecumseh, Mich.

[22] Filed: May 26, 1971 211 Appl. No.: 147,146

UNITED STATES PATENTS Valbjorn et a1 ..4l7/3l2 X Gannaway ...417/902 X [4 1 Oct. 17,1972

Primary Examiner-Robert M. Walker Attorney-Barnes, Kisselle, Raisch & Choate [57] ABSTRACT A muffler construction for a hermetic compressor wherein the muffler is made up of half-shell body and cover members connected together with their open ends facing one another and having matching ribs arranged at an acute angle to the gas flow path between the inlet and outlet of the muffler. The surfaces of the juxtaposed peripheral walls and ribs adjacent the open end of each member are coplanar. A flat sealing gasket is disposed between the members coextensive with the juxtaposed surfaces of the peripheral walls of the members. Hence, the gasket serves to space the juxtaposed surfaces of the ribs a predetermined distance apart to thereby define ,wide and thin flow passages successively communicating the muffler chambers formed by the transverse ribs and associated side and end walls of the members.

18 Claims, 6 Drawing Figures PATENTEUOBI 11 I972 l JII' INVENTOR" PAUL B. HOVER ATTORNEYS PAIENTEDncnnsn I 8.698.840

.suwaurz IN EN R V PAUL Rf/OVER ATTORNEYS COMPRESSOR MUFFLER CONSTRUCTION This invention relates to a gas pump muffler construction and more particularly to a discharge muffler formed as part of a cylinder head in a piston-type hermetic compressor.

An object of the present invention is to provide an improved muffler construction for a gas pump which is economical to manufacture, which has an improved dampening capability for pressure pulses induced by the pump to provide a reduced noise level with less flow restriction losses, and which can be readily adapted to the volumetric flow rate for various sizes of gas pumps in a very simple and inexpensive manner.

Another object is to provide a hermetic compressor having an improved muffler construction of the type described above integrated into a combination muffler and cylinder head in a compact arrangement which is adapted to be made by economical, high volume casting processes.

Other objects, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a vertical sectional view through the hermetic casing of a reciprocating piston-type hermetic compressor, with portions of the compressor broken away and shown in vertical center section to better illustrate details of the improved muffler construction of the present invention embodied therein.

FIG. 2 is an exploded perspective view illustrating the cover, gasket and body parts of the muffler construction of the present invention, .the body being shown fragmentarily.

FIG. 3 is a vertical elevation of the body part of the muffler shown by itself looking into the open end thereof, or from left to right as viewed in FIG. 1.

FIG. 4 is a vertical elevation of the cover part of the muffler shown by itself and likewise as viewed looking into its open end, or from right to left as viewed in FIG. 1.

FIGS. 5 and 6 are horizontal sectional views taken respectively on the lines V-V and VIVl of FIG. 3 but with the niuffler parts in assembled relation.

Referring in more detail to FIG. 1, by way of illustration, the muffler construction of the invention is shown applied to a gas pump in the form of a hermetic motorcompressor unit 10 wherein most of the compressor components are of well-known conventional construction, as will be recognized by those skilled in the art. Thus, compressor unit 10 has a hermetically sealed casing 12 in which is resiliently suspended a vertical shaft, reciprocating piston-type compressor 14 and associated superimposed electric motor 16 for driving the same. A cylinder block 18 of the compressor has a piston 20 reciprocally received in a cylinder bore 22 thereof. A valve plate 24 is secured to the end of cylinder block 18 and has mounted thereto conventional leaf-type intake and discharge valves 26 and 28 respectively for controlling flow of gaseous refrigerant into and out of the pump chamber 30.

In accordance with the present invention, a combined cylinder head and discharge muffler assembly 32, hereinafter referred to as muffler 32, is secured to cylinder block 18 in overlying relation to valve plate 24. Suitable gaskets 34 and 36 are disposed one between block 18 and plate 24 and the other between plate 24 and the cylinder head portion 38 of muffler 32. Muffler 32 consists of three principal parts; namely, body 40, cover 42 and gasket 44 (see also FIGS. 2, 3 and 4). Body 40 is preferably a single cast part extending almost the full height of casing 12 and being about half as wide as it is long, with the cylinder head portion 38 comprising the lower half of body 40. Portion 38 has a generally U-shaped discharge chamber 46 (FIG. 3) which registers with discharge valve 28 and the associated discharge ports in plate 24 controlled thereby, and a centrallydisposed suction chamber 48 which overlies intake valve 26 and associated intake ports. An array of four holes 50, 52, 54 and 56 are provided in portion 38 for receiving the mounting studs (not shown) which detachably secure muffler 32 to block 18.

The upper half of body 40 comprises the muffler portion 58 thereof and generally is in the form of a rectangular half shell open in a direction facing the cylinder block. Muffler portion 58 comprises a pair of upright parallel side walls 60, 62 and parallel bottom and top walls 64, 66 respectively. The side and end walls 6066 are cast integrally with a generally flat outer wall 68 (FIG. 1) which extends vertically the entire length of muffler 32. A plurality of internal ribs, preferably two in number, comprising a lower rib 70 and an upper rib 72, extend transversely between the side walls 60, 62 to thereby divide the muffler portion 58 into three vertically aligned pockets 74, 76 and 78. Preferably, ribs 70, 72 converge toward one another to a junction with side wall 62 at an angle of about 75 therewith so that the angle A (FIG. 3) between ribs 70 and 72 is about 30. Ribs 70 and 72 are thus disposed in non-parallel relation to each other as well as to end walls 64 and 66 and side walls 60 and 62.

Communication between discharge chamber 46 and pocket 74 is provided by a cored passageway extending between the outer wall 68 and a central bridge portion 82 (FIGS. 1 and 3) of bottom wall 64. The discharge outlet of muffler 32 comprises a threaded passageway 84 (FIGS. 2 and 3) extending through the upper end of side wall 62 and terminating at its outer end in an offset portion 86 so that the axis of passageway 84 is disposed at an angle of about 25 to the plane of the drawing in FIG. 3. Three holes 90, 92 and 94 extend through portion 58 for receiving associated mounting bolts 90a, 92a and 94a, and suitable bosses and fillets are provided around the bolt holes integral with the respectively adjacent portions of the walls and ribs associated therewith as best seen in FIGS. 2 and 3.

It is to be noted that the surfaces 61, 63, 65 and 67 of peripheral walls 60, 62, 64 and 66 respectively, and the surfaces 71 and 73 of ribs 70 and 72 respectively, disposed at the open end of portion 58 are coplanar with one another as well as with the surfaces of the peripheral and interior walls provided in the cylinder head portion 38 of body 40.

Cover 42 also is in the form of a rectangular half shell and is provided with side walls 60' and 62, end walls 64' and 66' and interior ribs 70 and 72' dividing the same into three vertically aligned pockets 74', 76' and 78', these parts being given the same reference numerals raised by a prime as the like elements of half shell 58 of body 40 to indicate the correspondence and matching relationship thereof. Cover 42 is thus adapted to be juxtaposed as shown in FIG. 2 with its open end facing the open end of portion 58 so that the peripheral walls and interior ribs of the two parts match up in registering relation when assembled together as shown in FIG. 1. If desired, the upper portion of side wall 62' of cover 42 may be offset inwardly at 62a (FIG. 4) to match up with the inward offset formed by the widened portion 62a in wall 62 of body portion 58 (FIG. 3) in order to provide clearance for the inlet end 100 (FIG. 1) of a discharge tube 102. Tube end 100 is threadably secured in passageway 84 and tube 102 extends around the upper end of motor 16 to a through-wall connector mounted in casing 12 (not shown). The peripheral walls and interior ribs of cover 42 also have coplanar surfaces 61', 63', 65', 67, 71 and 73' at the open end thereof.

Gasket 44 comprises a thin, flat, rectangular member made of suitable gasket material such as neoprene asbestos and is shaped to coextensively sealingly engage the flat, parallel and juxtaposed surfaces 61, 61', 63, 63, 65, 65, 67 and 67' of the side and end walls of half shell 58 and cover 42. Gasket 44 has suitably contoured and apertured inward protuberances 110, 112 and 114 which sealingly engage the surfaces of the bosses provided around holes 90, 92 and 94 respectively, as best seen by the position of gasket 44 against body portion 58 indicated in phantom in FIG. 2. Thus, when cover 42 and gasket 44 are assembled to body 40 as shown in FIG. 1, gasket 44 is clamped therebetween in sealed relation by the three mounting bolts 90a, 92a and 94a.

The complementary pockets 74 and 74' define a first muffler chamber into which gaseous refrigerant compressed to a high pressure by compressor 14 enters via discharge chamber 46 and passageway 80 for expansion in chamber 74-74. Communication between this chamber and the next successive muffler chamber 76-76 is established by the clearance space 116 (FIGS. 1 and defined between the juxtaposed flat surfaces 71 and 71' of ribs 70 and 70 and the inner edges of the gasket 44. The gas further expands in chamber 76-76 and then flows through the next passageway 118 defined between the juxtaposed flat surfaces 73 and 73' of ribs 72 and 72' and the inner edges of gasket 44 (FIGS. 1 and 6). The compressed gas expands again in chamber 78-78 and then exits therefrom through the port 84 into discharge tube 102 for delivery to the high side of the refrigeration system connected to the compressor.

From the foregoing description, it will now be apparent that the improved muffler and compressor construction of the present invention provides several advantageous features. Both of the major parts, i.e., body 40 and cover 42, are configurated for economical mass-production casting, with only one movable core being required for passageway 80. The cylinder head and muffler structure are formed as an integral subassembly 32, thereby facilitating assembly of the compressor. Due to the flat coplanar relationship of the surfaces of the juxtaposed body and cover, and the spacing function of the gasket, the size of the communicating passageways 116 and 118 can be readily varied in production by selecting a supply of gaskets 44 of predetermined thickness. That is, gasket 44 serves as a spacer as well as a sealing gasket and hence its thickness determines the cross-sectional area of passages 116 and 118. Therefore, the transfer passages 116 and 118 are automatically formed merely by the interposed gasket, eliminating the need for connector tubes or machining grooves or notches in the partitioning ribs 70, 72, and 72' of the body and cover parts.

Since, in accordance with known muffler pressure wave attenuation theory, the successive transfer passages 80, 116 and 118 and chambers 46, 76-76' and 78-78 are roughly analogous to inductors, resistors and capacitors respectively of electrical filter theory, the flow capacity and noise reduction characteristics of the muffler can be varied and adjusted in accordance with the volumetric capacity and frequency of the particular model of gas pump or compressor with which the muffler construction is used.

, Muffler 32 is preferably designed to be non-resonant so that it is insensitive to frequency, the diagonal internal ribs 70, 70', 72 and 72 preventing a resonant cavity condition from occurring. Thus, in the preferred arrangement of muffler 32, the chambers are in series in a straight line due to the parallel side walls of the body and cover, but the wall surface surrounding the entrance port to each chamber is not parallel to any other wall in that chamber. This helps attenuate the pressure pulsations which are created in the refrigerant gas as it is forced by piston 20 past discharge valve 28 because as each pressure wave opens up into each chamber, its direction of propigation will be non-perpendicular to the opposite chamber wall, thereby causing the wave to be split up. Phase shifting thus will occur in' the sound wave front as it is mixed and jumbled up with preceding and successive sound waves in the chamber to thereby better muffle the discharge noise of the compressor.

With the above construction of muffler 32, it has been found that pressure pulsations are more effectively dampened and the noise level at the output of the muffler is significantly reduced. Tests have also indicated that it is possible to obtain equal, reduction in both noise and pressure pulses, but with less restriction to flow of gas through the muffler via the passages between the chambers, by using the long, thin passages 116 and 118 as compared to the holes, tubes or notches or prior art mufflers. This in turn improves overall perforrnance of the compressor.

It is also to be noted that passageway 80 is offset in a direction parallel to the plane of the drawing in FIG. 1 from the location of passageway 116, and that discharge outlet 94 is oriented transversely to the direction of flow of the gases entering chamber 78-78'. These relationships also help dampen noise within the muffler. Muffler 32 also makes optimum use of the space available in compressor unit 10 by positioning cover 42 above block 18 between motor 16 and body 40.

I claim:

1. In a hermetic compressor having a hermetic casing for receiving refrigerant gas and a refrigerant gas pump disposed in said casing including a pumping chamber, the improvement comprising a muffler having a first port connected to said pumping chamber and a second port spaced from said first port and operably connected to the refrigeration gas circuit of said compressor, said muffler comprising a body member and a cover member each having a half-shell portion open at one end and closed at the opposite end by an'outer wall with a peripheral wall extending around the edge of said outer wall, each of said members having a plurality of ribs extending in acute angle relationship relative to one another between opposite portions of said peripheral wall and defining with the associated outer peripheral walls of the associated member a series of pockets disposed in succession between said ports, said peripheral wall and ribs of each of said members having coplanar surfaces adjacent the open end thereof, said members being connected together with their open ends facing one another and said ribs juxtaposed in matching relationship, and a gasket disposed between and in sealing engagement with said coplanar surfaces of the juxtaposed peripheral walls of said members whereby said coplanar surfaces of said ribs of said body member are spaced from the juxtaposed coplanar surfaces of said ribs of said cover member to define flow passages therebetween communicating with said pockets. I

2. The compressor as defined in claim 1 wherein each said half-shell portion is generally rectangular in shape and wherein said peripheral wall is composed of spaced side walls extending longitudinally of said muffler and spaced end walls transverse to said side walls, said ribs comprising first and second ribs in each member converging at one end centrally of one of said side walls and each extending at an acute angle therefrom toward individual junctions with the other of said side walls.

3. The compressor as defined in claim 2 wherein said ribs of each of said members each extend at about a 75 angle from said one wall and diverge at about a 30 angle relative to one another.

4. The compressor as defined in claim 2 wherein said pockets of each of said members consist of three in-line pockets made up of a center pocket defined by said first and second ribs and associated side wall, and first and second end pockets disposed on opposite sides of said center pocket with said first and second ribs respectively serving as one wall thereof, said first and second ports opening respectively into said first and second pockets at points disposed remote from said first and second ribs respectively.

5. The compressor as defined in claim 4 wherein said second port is disposed in the portion of one of said side walls defining in part said second pocket.

6. The compressor as defined in claim 5 wherein said first port comprises a passage extending through said end wall of said body member associated with said first pocket approximately midway between said side walls.

7. The compressor as defined in claim 6 wherein said one of said side walls having said second port therein comprises a side wall of said body member.

8. The compressor as defined in claim 1 wherein said pump comprises a cylinder block having a piston reciprocable horizontally therein and an electric motor operably connected to reciprocate said piston and superimposed on said block with its rotational axis upright, said body member having an extension at one end thereof juxtaposed to said cylinder block of said pump serving as a cylinder head therefor and having a discharge chamber therein communicating said pumping chamber with said first port, said second port being connected to a discharge conduit leading to the exterior of said casing.

9. The compressor as defined in claim 8 wherein said cover member is coextensive only with said half-shell portion of said body member and is disposed laterally adjacent said motor above said cylinder' block and on the same said of said body member as said cylinder block. v

10. The compressor as defined in claim 1 wherein said gasket has a uniform thickness selected in accordance with the length of the juxtaposed surfaces of said ribs extending between the inner edges of said gasket so that the cross-sectional area of each of said flow passages is correlated. with the volumetric flow rate of the refrigerant gas being pumped by'said pump through said muffler.

1 l. A muffler for use in a hermetic compressor comprising a bodymember and a cover member each having a half-shell portion open at one end and closed at the opposite end by an outer wall with a peripheral wall extending around the edge of said outer wall, said muffler having an inlet port and an outlet port spaced longitudinally of said muffler from said inlet port, each of said members having a plurality of ribs extending in acute angle relationship relative to one another between opposite portions of said peripheral wall and defining with the associated outer peripheral walls of the associated member a series of pockets disposed in succession between said ports, said peripheral wall and ribs of each of said members having coplanar surfaces adjacent the open end thereof, said members being connected together with their open ends facing one another and said ribs juxtaposed in matching relationship, and a gasketdisposed between and in sealing engagement with said coplanar surfaces of the juxtaposed peripheral walls of said members whereby said coplanar surfaces of said ribs of said body member are spaced from the juxtaposed coplanar surfaces of said ribs of said cover member to define flow passages therebetween communicating withsaid pockets.

- 12. The muffler as defined in claim 11 wherein each of said peripheral walls is composed of spaced side walls extending longitudinally of said muffler and spaced end walls transverse to said side walls, said ribs comprising first and second ribs in each member converging at one of said side walls and each extending therefrom toward individual junctions with the other of said side walls.

13. The muffler as defined in claim 12 wherein said ribs of each of said member each extend at about a angle from said one wall and diverge at about a 30 angle relative to one another.

14. The muffler as defined in claim 11 wherein said pockets of each of said members consist of three in-line pockets made up of a center pocket defined by said first and second ribs and associated side walls, and first and second end pockets disposed on opposite sides of said center pocket with said first and second ribs respectively serving as one wall thereof, said first and second ports opening respectively into said first and second pockets at points disposed remote from said first and second ribs respectively.

15. The muffler as defined in claim 11 including an extension at one end thereof forming a cylinder head 17. The muffler as defined in claim 16 wherein said outlet port is disposed in one of said side walls defining in part said second pocket of said body member.

18. The muffler as defined in claim 17 wherein said inlet port comprises a passage extending through said end wall of said body member associated with said first pocket between said discharge chamber and said first pocket of said body member. 

1. In a hermetic compressor having a hermetic casing for receiving refrigerant gas and a refrigerant gas pump disposed in said casing including a pumping chamber, the improvement comprising a muffler having a first port connected to said pumping chamber and a second port spaced from said first port and operably connected to the refrigeration gas circuit of said compressor, said muffler comprising a body member and a cover member each having a half-shell portion open at one end and closed at the opposite end by an outer wall with a peripheral wall extending around the edge of said outer wall, each of said members having a plurality of ribs extending in acute angle relationship relative to one another between opposite portions of said peripheral wall and defining with the associated outer peripheral walls of the associated member a series of pockets disposed in succession between said ports, said peripheral wall and ribs of each of said members having coplanar surfaces adjacent the open end thereof, said members being connected together with their open ends facing one another and said ribs juxtaposed in matching relationship, and a gasket disposed between and in sealing engagement with said coplanar surfaces of the juxtaposed peripheral walls of said members whereby said coplanar surfaces of said ribs of said body member are spaced from the juxtaposed coplanar surfaces of said ribs of said cover member to define flow passages therebetween communicating with said pockets.
 2. The compressor as Defined in claim 1 wherein each said half-shell portion is generally rectangular in shape and wherein said peripheral wall is composed of spaced side walls extending longitudinally of said muffler and spaced end walls transverse to said side walls, said ribs comprising first and second ribs in each member converging at one end centrally of one of said side walls and each extending at an acute angle therefrom toward individual junctions with the other of said side walls.
 3. The compressor as defined in claim 2 wherein said ribs of each of said members each extend at about a 75* angle from said one wall and diverge at about a 30* angle relative to one another.
 4. The compressor as defined in claim 2 wherein said pockets of each of said members consist of three in-line pockets made up of a center pocket defined by said first and second ribs and associated side wall, and first and second end pockets disposed on opposite sides of said center pocket with said first and second ribs respectively serving as one wall thereof, said first and second ports opening respectively into said first and second pockets at points disposed remote from said first and second ribs respectively.
 5. The compressor as defined in claim 4 wherein said second port is disposed in the portion of one of said side walls defining in part said second pocket.
 6. The compressor as defined in claim 5 wherein said first port comprises a passage extending through said end wall of said body member associated with said first pocket approximately midway between said side walls.
 7. The compressor as defined in claim 6 wherein said one of said side walls having said second port therein comprises a side wall of said body member.
 8. The compressor as defined in claim 1 wherein said pump comprises a cylinder block having a piston reciprocable horizontally therein and an electric motor operably connected to reciprocate said piston and superimposed on said block with its rotational axis upright, said body member having an extension at one end thereof juxtaposed to said cylinder block of said pump serving as a cylinder head therefor and having a discharge chamber therein communicating said pumping chamber with said first port, said second port being connected to a discharge conduit leading to the exterior of said casing.
 9. The compressor as defined in claim 8 wherein said cover member is coextensive only with said half-shell portion of said body member and is disposed laterally adjacent said motor above said cylinder block and on the same said of said body member as said cylinder block.
 10. The compressor as defined in claim 1 wherein said gasket has a uniform thickness selected in accordance with the length of the juxtaposed surfaces of said ribs extending between the inner edges of said gasket so that the cross-sectional area of each of said flow passages is correlated with the volumetric flow rate of the refrigerant gas being pumped by said pump through said muffler.
 11. A muffler for use in a hermetic compressor comprising a body member and a cover member each having a half-shell portion open at one end and closed at the opposite end by an outer wall with a peripheral wall extending around the edge of said outer wall, said muffler having an inlet port and an outlet port spaced longitudinally of said muffler from said inlet port, each of said members having a plurality of ribs extending in acute angle relationship relative to one another between opposite portions of said peripheral wall and defining with the associated outer peripheral walls of the associated member a series of pockets disposed in succession between said ports, said peripheral wall and ribs of each of said members having coplanar surfaces adjacent the open end thereof, said members being connected together with their open ends facing one another and said ribs juxtaposed in matching relationship, and a gasket disposed between and in sealing engagement with said coplanar surfaces of the juxtaposed peripheral wAlls of said members whereby said coplanar surfaces of said ribs of said body member are spaced from the juxtaposed coplanar surfaces of said ribs of said cover member to define flow passages therebetween communicating with said pockets.
 12. The muffler as defined in claim 11 wherein each of said peripheral walls is composed of spaced side walls extending longitudinally of said muffler and spaced end walls transverse to said side walls, said ribs comprising first and second ribs in each member converging at one of said side walls and each extending therefrom toward individual junctions with the other of said side walls.
 13. The muffler as defined in claim 12 wherein said ribs of each of said member each extend at about a 75* angle from said one wall and diverge at about a 30* angle relative to one another.
 14. The muffler as defined in claim 11 wherein said pockets of each of said members consist of three in-line pockets made up of a center pocket defined by said first and second ribs and associated side walls, and first and second end pockets disposed on opposite sides of said center pocket with said first and second ribs respectively serving as one wall thereof, said first and second ports opening respectively into said first and second pockets at points disposed remote from said first and second ribs respectively.
 15. The muffler as defined in claim 11 including an extension at one end thereof forming a cylinder head adapted to overlie a cylinder block of the compressor and having a discharge chamber therein communicating with said inlet port, said second port being adapted for connection to a discharge conduit leading to the exterior of the compressor.
 16. The muffler as defined in claim 15 wherein said cover member is coextensive only with said half-shell portion of said body member and said cylinder head extension protrudes therebeyond as an extension of said body member.
 17. The muffler as defined in claim 16 wherein said outlet port is disposed in one of said side walls defining in part said second pocket of said body member.
 18. The muffler as defined in claim 17 wherein said inlet port comprises a passage extending through said end wall of said body member associated with said first pocket between said discharge chamber and said first pocket of said body member. 